A systematic review to evaluate the efficacy of 5-aminosalicylates for induction of remission or clinical response in patients with mild to moderately active Crohn's disease is described. The effect of either high (3 to 4.5 g/day) or low dose (1 to 2 g/day) 5-aminosalicylic acid was similar to that of placebo. Overall, sulfasalazine was not superior to placebo and was inferior to glucocorticoids for the treatment of mild to moderately active Crohn's disease. Neither published nor unpublished data support any use of 5-aminosalicylates for the treatment of Crohn's disease.